Air–soil exchange of organochlorine pesticides in a sealed chamber

So far little is known about air–soil exchange under any sealed circumstances(e.g., in plastic and glass sheds), which however has huge implications for the soil–air–plant pathways of persistent organic pollutants including organochlorine pesticides(OCPs). A newly designed passive air sampler was tested in a sealed chamber for measuring the vertical concentration profiles of gaseous phase OCPs(hexachlorocyclohexanes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs)). Air was sampled at 5, 15, and 30 cm above ground level every 10 th day during a 60-day period by deploying polyurethane foam cylinders housed in acrylonitrile butadiene styrene-covered cartridges. Concentrations and compositions of OCPs along the vertical sections indicated a clear relationship with proximity to the mixture of HCHs and DDTs which escapes from the soils. In addition, significant positive correlations were found between air temperatures and concentrations of HCHs and DDTs. These results indicated revolatilization and re-deposition being at or close to dynamic pseudo-equilibrium with the overlying air. The sampler used for addressing air–soil exchange of persistent organic pollutants in any sealed conditions is discussed.     

Effects of elevated CO2 on dynamics of microcystin-producing and non-microcystin-producing strains during Microcystis blooms

In an attempt to elucidate the effects of different CO2concentrations(270, 380, and 750 μL/L) on the competition of microcystin-producing(MC-producing) and non-MC-producing Microcystis strains during dense cyanobacteria blooms, an in situ simulation experiment was conducted in the Meiliang Bay of Lake Taihu in the summer of 2012. The abundance of total Microcystis and MC-producing Microcystis genotypes was quantified based on the 16 S r DNA and mcy D gene using real-time PCR. The results showed that atmospheric CO2 elevation would significantly decrease the p H value and increase the dissolved inorganic carbon(DIC) concentration.Changes in CO2 concentration did not show significant influence on the abundance of total Microcystis population. However, CO2 concentrations may be an important factor in determining the subpopulation structure of Microcystis. The enhancement of CO2 concentrations could largely increase the competitive ability of non-MC-producing over MC-producing Microcystis, resulting in a higher proportion of non-MC-producing subpopulation in treatments using high CO2 concentrations. Concurrently, MC concentration in water declined when CO2 concentrations were elevated. Therefore, we concluded that the increase of CO2 concentrations might decrease potential health risks of MC for human and animals in the future.     

关于美国城市环境管理的启示

城市环境管理是我国环保工作的重点之一,美国城市环境管理中的经验和教训,可以为我们提供一些借鉴。     

Particle concentration effect in adsorption/desorption of Zn(Ⅱ) on anatase type nano TiO_2

Adsorption/desorption in a new Zn(Ⅱ)-TiO_2 adsorption system was investigated at different particle concentrations(C_p).TEM,SEM and XRD analyses revealed that the TiO_2 particles were an aggregation of nano-sized(approximately 10 nm)pure anatase-type TiO_2. Adsorption experiments were carried out with particle concentrations of 100,400 and 1000 mg/L,and their adsorption isotherms were found to decline successively,showing an obvious C_p effect.Desorption experiments indicated that adsorption in this system was irreversible,and the irreversibility increased with increasing C_p.These phenomena could be explained by the MEA(metastable equilibrium adsorption)theory and the C_p effect could be modeled well with an MEA-Freundlich-type C_p effect isotherm equation. This study may help understand environmental behavior of contaminants on ultrafine natural particles.     

不同氮肥对油菜B与Mo吸收的影响

利用盆栽试验研究了潮土中不同氮肥对油菜硼钼吸收的影响，结果表明，前期(5周)施氮并没有促进油菜的生长，而且大部分氮肥对油菜生长表现抑制作用，氯化铵处理的作用最大，硫酸铵和尿素处理次之，硝酸铵处理再次之；不同氮肥均有抑制油菜生长前期(5周)硼吸收和累积的作用，其中以氯化铵、硝酸铵和尿素的作用为甚；不同氮肥同样抑制油菜生长前期(5周)对钼的吸收和累积，以硫酸铵处理作用最突出，氯化铵处理次之。但随着时间的推移，10、15周不同氮肥大多促进油菜的生长，增加油菜对硼钼的吸收和累积，且各氮肥处理间的差异逐步减小。     

Study on the water quality of the Taihu Lake using genotoxicological methods

ＳｔｕｄｙｏｎｔｈｅｗａｔｅｒｑｕａｌｉｔｙｏｆｔｈｅＴａｉｈｕＬａｋｅｕｓｉｎｇｇｅｎｏｔｏｘｉｃｏｌｏｇｉｃａｌｍｅｔｈｏｄｓＷｕＱｉｎｇｌｏｎｇ，ＣｈｅｎＫａｉｎｉｎｇＮａｎｊｉｎｇＩｎｓｔｉｔｕｔｅｏｆＧｅｏｇｒａｐｈｙａｎｄＬｉｍｎｏｌ...     

Immobilization of microorganisms using carrageenan gels coated with chitosan and application to biodegradation of 4 chlorophenol

Ｉｍｍｏｂｉｌｉｚａｔｉｏｎｏｆｍｉｃｒｏｏｒｇａｎｉｓｍｓｕｓｉｎｇｃａｒａｇｅｎａｎｇｅｌｓｃｏａｔｅｄｗｉｔｈｃｈｉｔｏｓａｎａｎｄａｐｐｌｉｃａｔｉｏｎｔｏｂｉｏｄｅｇｒａｄａｔｉｏｎｏｆ４ｃｈｌｏｒｏｐｈｅｎｏｌＷａｎｇＪｉａｎｌｏｎｇ...     

大港海滨盐土的腐蚀性研究

含可溶性盐量多、含水量高、电阻率极低等土壤性质决定了大港海滨盐土具有很强的腐蚀性。本次试验主要研究了碳钢、ＬＹ１１铝合金、Ｈ６２黄铜、１Ｃｒ１３不锈钢、１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢几种金属材料经过１、３、５年三个试验周期的腐蚀行为及特征     

Vertical fluxes of volatile mercury over soil surfaces in Guizhou Province, China

ＶｅｒｔｉｃａｌｆｌｕｘｅｓｏｆｖｏｌａｔｉｌｅｍｅｒｃｕｒｙｏｖｅｒｓｏｉｌｓｕｒｆａｃｅｓｉｎＧｕｉｚｈｏｕＰｒｏｖｉｎｃｅ，ＣｈｉｎａＦｅｎｇＸｉｎｂｉｎ，ＣｈｅｎＹｅｃａｉ，ＺｈｕＷｅｉｇｕｏＳｔａｔｅＫｅｙＬａｂｏｒａｔｏｒｙｏｆＥｎｖｉｒ...     

Deformity frequencies of benthic marine diatoms associated with contaminated sediments in Hong Kong

ＤｅｆｏｒｍｉｔｙｆｒｅｑｕｅｎｃｉｅｓｏｆｂｅｎｔｈｉｃｍａｒｉｎｅｄｉａｔｏｍｓａｓｏｃｉａｔｅｄｗｉｔｈｃｏｎｔａｍｉｎａｔｅｄｓｅｄｉｍｅｎｔｓｉｎＨｏｎｇＫｏｎｇＭｉｃｋＤｉｃｋｍａｎＥｃｏｌｏｇｙａｎｄＢｉｏｄｉｖｅｒｓｉｔｙＤｅｐａｒｔ...